The objective of this application is for the Department of Urology, Mayo Clinic, Rochester, Minnesota, to become one of the Prostate Evaluation and Treatment Centers (PETC?s) as part of the Minimally Invasive Surgical Therapies (MIST) Treatment Consortium for BPH described in RFA DK-01-024. The purpose of the MIST consortium is to carry out collaborative studies of minimally invasive surgical treatments for lower urinary tract symptoms (LUTS) and benign prostatic hyperplasia (BPH) over the next five years. Minimally invasive surgical therapies for BPH recently have been recognized as an efficient and cost-effective alternative to standard transurethral resection of the prostate (TURP) and open prostatectomy for certain patients with typical symptoms of prostatism. Most urologists now recognize that minimally invasive surgical therapies occupy a useful niche between pharmacologic therapy and surgical procedures which require inpatient hospitalization. However, as stated in the RFA, published reports about minimally invasive therapies are highly variable in entry criteria and have short periods of follow-up, inadequate documentation of follow-up and adverse events, and absence of information on post-surgical pharmacologic therapy. Most studies have been funded by the device makers and are probably not as objective as studies carried out by an independent group such as the MIST consortium. Because of documented interest in carrying out minimally invasive surgical therapies for BPH at this institution as well as past experience of being a useful member of collaborative consortia studying prostate diseases, we believe we can make a useful contribution to the study of Minimally Invasive Surgical Therapies for BPH as a PETC. As an example of the type of MIST research which could be performed in this initiative, we propose a prospective multicenter randomized Phase III comparison of high power KTP laser vaporization prostatectomy (LVP) versus transurethral microwave thermotherapy (TUMT) using the Urologix Targis T3 device. One hundred seventy patients would be randomized to each treatment arm. Follow-up period would be 2 years post-treatment.